Commonly aircraft based power generation systems use a three-stage main generation system. The stages include a permanent magnet generator (PMG) that provides power to a generator control unit. The generator control unit supplies control current to an exciter. The exciter transfers or generates 3-phase power on the rotor of the generator which is rectified by a 3-phase diode rectifier and fed to the rotating field winding of the main machine. The field winding of the main machine rotates, generating power that is fed to the aircraft loads. By adjusting the control current fed to the exciter, the main field winding current can be controlled to maintain a fixed output voltage on the main machine. Generation systems are designed to saturate magnetically such that a maximum voltage cannot be exceeded even if the maximum possible control current is supplied to the exciter due to a system failure mode when operating at normal operating temperatures. However, if the maximum possible control current is supplied to the exciter when operating at very low temperatures, the output voltage of the main generator can exceed the capability of the power system to withstand without damage.